Análise da vulnerabilidade erosiva da Bacia Hidrográfica Colônia Antônio Aleixo, Manaus-AM

Abstract

The main objective of this dissertation was analyze the vulnerability of the Colônia Antônio Aleixo’ watershed (Manaus – AM) to gullies considering human and nature aspects. The watershed is located at Manaus’ east zone, has an area of 23, 94 km2 and is composed of nine neighborhoods. To achieve the main goal, were developed specifics objectives: Characterization of area pedo-geomorphological’s aspects; description of the natural and urban attributes of the area; monitoring gullies; correlation between slope and gullies mofometric aspects. The methodology divided in 4 phases: 1) Literature revision; 2) Field Work; 3) Cabinet work and lab analyze; and 4) Dissertation writing. The work field aimed to characterize the fisiographic and urban aspect, which were pertinent to the development of gully incisions. Further realized one topossequence on a representative slope at the Colônia Antônio Aleixo’ watershed, where were analyzed the soil physic characteristics for instance Texture, Bulk and Particle Density and Porosity, soil chemical characteristics such as pH, macro and micronutrients, besides the infiltration and soil resistance test. It were calculated morphometric, drainage and topographic aspects of the basin. Were developed maps of hypsometric, slopes, landform, and land use and land cover. It developed the natural vulnerability map to erosive process based on the landform and slope maps, and then environmental vulnerability map based in the same criteria associated with the map of land use and land cover. It observed that the pedo-geomophological characteristics show great influence at the development to the erosive process considering the soil susceptibility to erosion. Moreover, the impact of the urban expansion is visible at development of incisions, considering the great number of gullies at the basin (n=22) located next to streets. In general, the basin show development of morphogenetics process over the pedogenetics process, being a result of the vulnerability of the area in face of erosion process. Being represented by the great number of incisions and their impacts at the landscape and the drainage network.